This invention relates to rail electrification systems such as used in connection with vehicles, cranes and the like, and more particularly to the construction of the rail members and joints employed with such systems.
In the past many types of conductor rails and connector devices or joints have been proposed and produced, to provide an essentially continuous conductor surface for engagement with current collecting shoes or brushes of a traveling piece of equipment. In recent years the trend has been to the use of extruded aluminum rail sections arranged to carry the current, and stainless steel contact liners or facing strips which are coextensive with the rail sections, arranged for engagement with the traveling collector or shoe. The rail sections, in many later installations, were made with T-slots by which convenient connection can be established with hanger insulators as well as rail connectors or joints which are adapted to couple together adjoining end portions of the rails.
While the prior rail constructions of this general type have in most instances proved to be generally satisfactory, as more exacting demands were made for improved performance and operating characteristics, the prior devices were found to be lacking because sufficiently precise positioning and alignment of the rail end portions was not had, and also because there was insufficient reduction of electrical losses resulting from the joint conductivity between adjoining rail sections. Misalignment of prior rail sections also resulted in objectionable noise, and caused increased shoe or collector wear. In addition, the incorporation of heater wires in the rail members was at best a difficult or time consuming task and sometimes caused tearing, and they were remote from the contact liners.